It is easier to use mechanical fasteners, like nails and screws, but to add that look of first-class work, with smooth, metal free visible areas, nothing will do the job like a direct joint between parts, bonded with glue. Of course, the type of joint you need depends on a variety of factors, like the nature of the materials, the function of the joint, strength and appearance, available equipment, and your own level of skill. Joinery may be intimidating to the beginner, but, like any other building skill, all it takes is a bit of practice.
Here we dissect the workings of two primary joints, the edge joint and the mortise and tenon. WIth these joints, you can build a wide array of furniture and tackle a number of woodworking projects without having to rely on unsightly (although time-saving) nails and screws.
Step 1: Edge Joints
For edge joining, the mating surfaces must be flat and square to both faces of the board. To achieve this, first scribe a straight reference line on one surface, using a long straightedge. Then clamp this board to the side of your worktable and use a bench plane to flatten the edge. Check your progress relative to your reference line frequently. And check for square frequently with a combination square.
Once you'e satisfied with the edge on the first board, repeat the same process on the mating board. When you've flattened this edge, lay the two boards together on a flat surface and check for fit. Usually some additional work will be required to get a perfect joint. When you've achieved it, just spread glue on both mating edges.
Step 3: Doweling
For standard 13/16-in.-thick stock, 1/4-in.-dia. x 1-in.-long dowels are a good choice. Start by laying out the dowel locations every 6 in. to 8 in. along the joint. Next, install the 1/4-in.-dia. bushing in your doweling jig and center the hole in the jig bushing over your first mark. Tighten the jig in place and bore a hole in the edge. Make sure that the hole is deep enough to allow a 1/16-in. space at each end of the dowel for excess glue. Repeat the same procedure for all the holes along the joint.
Birch dowel stock, in 36-in. lengths and in diameters from 1/8 in. to 1 in., is commonly available at hardware stores and lumberyards. When using this material, it's a good idea to cut a narrow groove down the length of each piece to create an escape route for excess glue. You can use the corner of a sharp chisel to scratch the side of the dowel. You also should slightly bevel both ends of the dowel with a piece of sand-paper. This bevel makes aligning the dowels in their mating holes easier.
Step 4: Tap Dowels
Step 5: Set Joint
Step 6: Mortise and Tenon
Beginners often avoid this joint because the skills required seem out of reach. But if you take care in layout and cutting, you can easily achieve good results. Of course, it's always a good idea to practice on some scrap wood first. The tools you'll need are a combination square, marking gauge, drill, doweling jig, backsaw and sharp chisel.
To lay out the joint, begin by marking the tenon shoulder line. This represents the length of the finished tenon, which is usually 1 in. to 1 1/2 in. long. Use a square and pencil to extend this shoulder mark to both sides and edges of the board.
Step 7: Make Guides
Step 8: Saw Joint
Step 9: Cut Waste Side
Step 10: Chisel Tenon
For a guide to using a chisel, check out our previous instructable on chiseling.
Step 11: Cut Top, Bottom
Step 12: Cut Length of Tenon
Step 13: Mortise
Step 14: Bore Holes
Step 15: Square Ends, Test Fit the Joint
Finally, test fit the joint. The tenon should be snug in the mortise, but you shouldn't have to force the parts together. If the joint is too tight, carefully pare the tenon cheeks with a sharp chisel until the fit is correct. If you need to remove just a bit of stock, use sandpaper. Once you're satisfied with the fit, apply glue to all the mating surfaces, and slide the pieces together. Clamp the assembly securely until the glue has dried.